Method and apparatus for the shrink-wrapping of packages

ABSTRACT

A method for packaging frame, coil or ring shaped articles stacked on a pallet with a shrink film wrapping. The articles are stacked on the pallet over a guide element which projects upwardly through a recess in the pallet. In some embodiments the articles are compressed after being covered with a shrink film wrapping. The wrapping is heat-shrunk about the stack of articles and portions of the pallet. In some embodiments the guide element is telescoping and is removed through the pallet recess after the wrapping is heat-shrunk.

United States Patent Hanemann June 19, 1973 [54] METHOD AND APPARATUS FOR THE 3,638,790 2/1972 Schmid et al 206/65 S SHRINK-WRAPPING F PACKAGES FOREIGN PATENTS 0R APPLICATIONS Inventorl Walter Hanemann, an f r /M 1,138,680 10/1962 Germany 53 30 Germany [73] Assignee: Feldmuhle Aktiengesellschaft, 'f Exami'fer-Granvme Custer Dusseldorg-Oberkassel, Germany Asslstam 1' Attorney-Charles B. Smith and Lee C. RObIl'lSOIl, Jr. [22] Filed: Feb. 12, 1971 21 Appl. No.: 114,824 ABSTRACT A method for packaging frame, coil or ring shaped arti- [52] U CL 53/24 53/30 cles stacked on a pallet with a shrink film wrapping. [5]] i CL B65; 53/02 The articles are stacked on the pallet over a guide ele- [58] Field of'gearch 53/13 30 159 ment which projects upwardly through a recess in the 53/184 T 29/5 pallet. in some embodiments the articles are compressed after being covered with a shrink film wrap- [56] References Cited ping. The wrapping is heat-shrunk about the stack of articles and portions of the pallet. In some embodi- UNITED S T PATENTS ments the guide element is telescoping and is removed 1,476,319 12/1923 Awgier 206/46T h h h ll t {@3655 after the wrapping is heat- 3,005,542 10/1961 Harrison... 53 13 x Shrunk 1,510,159 9/1924 Powell 206/46 T 3,522,688 8/1970 Kaliwoda et al..... 53/30 2 Claims, 3 Drawing Figures PAINTED- METHOD AND APPARATUS FOR THE SHRINK-WRAPPING OF PACKAGES BACKGROUND OF THE INVENTION The present invention relates to a method and apparatus for the shrink film wrapping of frame-shaped and particularly ring shaped compressible articles stacked on a pallet.

Frame-structures, such as window frames, and wire coils, coils of rope, and tires, are usually packed by first tying them together at several places and then wrapping the resultant bundle with crepe paper, tape or similar material. This generally requires a large amount of labor or expensive machines.

Another disadvantage of this prior wrapping technique is that even by tying together several articles and wrapping bundles of tied articles, sufficiently great adherence cannot be obtained between the individual articles to prevent them from sliding on each other. The bundle shifts on itself resulting in the damaging of the individual articles.

Furthermore the stacking of several bundles on top of one another is made extremely difficult and dangerous by the lack of stability of the bundles. This is due in part to the looseness of the packaging but also in part to the relatively high center of gravity of the stack of articles.

Another particular disadvantage in the case of bundles of coiled tubing, rope or wire is that after the loosening of the package the coils no longer have any firm guidance and the individual coil layers become entangled with each other upon removal of only a few meters of the packed material.

Such materials are commonly shipped on drums, mandrels or packed in containers to avoid these problems. Both of these possibilities require a relatively high amount of packing material and substantially increase the shipping weight. In addition, they also result in an increase in volume, so that the shipment of such coil, ring or frame-shaped articles is particularly uneconomical.

SUMMARY OF THE INVENTION The above and other disadvantages are overcomeby the method and apparatus of the present invention comprising stacking the frame-shaped articles upon a pallet over one or more guide elements which project upwardly through recesses in the pallet. After the articles are stacked, they are covered with a shrink film wrapping which is thereafter heat-shrunk about the stack and portions of the pallet.

For applications involving compressible articles, the stack is compressed after the wrapping and during the heat-shrinking process. In such embodiments the lower portion of the wrapping extends inwardly below the bottom of the pallet and in some embodiments is fastened to the pallet by nails, staples, or the like. In such embodiments the compression of the articles results in both a saving of volume and in increased stability of the stack because of the higher frictional forces acting between the articles due to the compressionoFurthermore, the center of gravity of the stack is lowered which also renders it more stable.

The number of stacks of articles arranged on a single pallet is dependent on the outside dimensions illustratively the diameter, of the articles to be stacked. For example, bicycle tires require a relatively large amount of stacking space and therefore only a few stacks would be placed on a single pallet whereas scooter tires, having a relatively smaller diameter, might be arranged in several stacks on a single pallet. For each stack of articles there is a pallet recess and a guide element projecting upwardly through the recess and the stack.

In one embodiment the guide elements are tele scopic. Such telescopic guide elements are particularly useful where the stack of articles is to be compressed.

After the wrapping has been heat-shrunk about the package the guide element is no longer necessary to prevent the articles from shifting. In order to reduce the weight of the package and to reduce the cost of the package materials, the guide element is withdrawn through the pallet recess.

The shrunk-on wrapping may be made of any of several well-known heat-shrinkable materials. Suitable heat-shrinkable materials might be polyethylene, polypropylene, polyvinyl chloi'ide, polyvinylidene chloride, or polyester. The wrapping material made of any of these compounds is specially treated by stretching it during formation so that it will shrink in predetermined directions when it is heated to a relatively high temperature, such as two hundred and twenty degrees centigrade. i

It is an object of the present invention to provide a more economical method of packaging goods stacked on a pallet.

It is another object of the invention to reduce-the manual work involved in packaging goods stacked on a pallet and to replace such manual work to the furthest extent possible with machine work. I

It is still another object of the invention to reduce the weight and volume of packages of goods stacked on a pallet.

It is a still further object of the invention to provide a stable, firm package for goods stacked on a pallet.

The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of certain preferred embodiments of the invention, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical view, in section, of one embodiment of the invention, including a plurality of compressible articles stacked upon a telescoping guide element;

FIG. 2 is a vertical elevational view, partly insection, of the finished package form of the embodiment of FIG. 1;

FIG. 3 is a plan view of a pallet of another embodiment of the invention;

DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS Referring now more particularly to FIG. 1 a pallet 10 is shown having a recess 12 through it. A guide element 14 is inserted through the recess prior to the stacking of articles 16 on the pallet. The articles are stacked over the guide element up to its height. The guide may be cylindrical or have a rectangular cross-section, depending on the shape of the articles to be stacked. Its outside dimensions and contour are matched to the internal dimensions of the articles so that the guide element reinforces the stack and prevents any substantial horizontal movement of the articles 16. A wrapping of heat-shrinkable material 18, generally in the form of an inverted bag, is placed over the stacked goods.

In situations where the articles 16 are compressible, for example in the case of automobile tires, a pressing foot 20 is lowered to compress the covered articles. The wrapping 18 is dimensioned such that its bottom edge 22 reaches the outside bottom edge 24 of the pallet when the articles 16 are compressed. The guide 14 has a telescoping upper section 26 to accommodate the shortened height of the stack due to the compression. The bottom edge 22 of the wrapping is tucked under the outside bottom edge 24 of the pallet and fastened to the pallet by nails 28, staples or the like as is more clearly shown in FIG. 2.

The pressing foot 20 retains the goods 16 in their compressed position until the wrapping 18 has been tightly shrunk about the goods with the application of heat by any of the usual methods including passing the stack and pallet through a shrinking oven.

The pressing foot may be mounted on a frame not shown or may be a free member such as weighted disc. When a shrinking oven is utilized, it is particularly convenient for the pressing foot 20 to be a free member.

After the heat-shrunk wrapping 18 has cooled and achieved its full strength, the pressing foot 20 is removed and the stack of articles is retained in its compressed state by the heat-shrunk wrapping 18 as is shown more clearly in FIG. 2.

Although the above description has illustratively referred to compressible automobile tires, in other embodiments the stacked articles may be incompressible, such as window frames. In .such cases the stackcompressing step is omitted. The wrapping in the case of frame shaped articles is in the form of a side-folded bag to more closely fit their shape.

Where the dimensions of the articles are such as to permit several stacks upon a single pallet, a plurality of pallet recesses and a plurality of guide elements are provided, each stack being formed over a separate guide element projecting upwardly through a separate pallet recess. The wrapping in such embodiments covers several stacks, but the compressing and heatshrinking steps are substantially the same as those described above in reference to the embodiment of FIGS. 1 and 2. A pallet 30 having a plurality of pallet recesses 32 for such a multistack embodiment is shown in FIG. 3.

The terms and expressions which have been employed here are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described, or portions thereof, it being recognized that various modifications are possible within the scope of the invention claimed.

What is claimed is:

l. A method of packaging goods stacked on a pallet comprising the steps of stacking the goods over a guide element projecting upwardly from the top surface of the pallet, covering the stack of goods with a wrapping of heat-shrinkable material, heat-shrinking the wrapping about the stack of goods and a portion of the pa]- let, and removing the guide element through a recess in the pallet after'the step of shrinking the wrapping.

2. A method of packaging goods stacked on a pallet comprising the steps of inserting .a guide element through a recess in the'pallet to project upwardly of the pallet, the guide element having external dimensions which provide a close fit with the internal dimensions of the goods to be stacked, stacking the goods in layers over the guide element, covering the stack of goods with a wrapping of heat-shrinkable material, compressing the stack of goods, fastening the lower portion of the wrapping to the underside of the pallet while simultaneously retaining the goods in their compressed state, heat-shrinking the wrapping about the stack of goods and a portion of the pallet, and removing the guide element from the stack of goods downwardly through the pallet recess. 

1. A method of packaging goods stacked on a pallet comprising the steps of stacking the goods over a guide element projecting upwardly from the top surface of the pallet, covering the stack of goods with a wrapping of heat-shrinkable material, heatshrinking the wrapping about the stack of goods and a portion of the pallet, and removing the guide element through a recess in the pallet after the step of shrinking the wrapping.
 2. A method of packaging goods stacked on a pallet comprising the steps of inserting a guide element through a recess in the pallet to project upwardly of the pallet, the guide element having external dimensions which provide a close fit with the internal dimensions of the goods to be stacked, stacking the goods in layers over the guide element, covering the stack of goods with a wrapping of heat-shrinkable material, compressing the stack of goods, fastening the lower portion of the wrapping to the underside of the pallet while simultaneously retaining the goods in their compressed state, heat-shrinking the wrapping about the stack of goods and a portion of the pallet, and removing the guide element from the stack of goods downwardly through the pallet recess. 